logic: C/C++ errors without location are now recorded for current main file

* such an error occurrs if a "-include" flag is provided with a non-existing file"

src/lib_cxx/data/parser/cxx/CxxDiagnosticConsumer.cpp

@@ -90,6 +90,11 @@ void CxxDiagnosticConsumer::HandleDiagnostic(clang::DiagnosticsEngine::Level lev
 			}
 
 			const clang::FileEntry* fileEntry = sourceManager.getFileEntryForID(sourceManager.getFileID(loc));
+			if (fileEntry == nullptr || !fileEntry->isValid())
+			{
+				fileEntry = sourceManager.getFileEntryForID(sourceManager.getMainFileID());
+			}
+
 			if (fileEntry != nullptr && fileEntry->isValid())
 			{
 				filePath = m_canonicalFilePathCache->getCanonicalFilePath(fileEntry);

src/test/CxxParserTestSuite.h

@@ -4057,6 +4057,17 @@ public:
 		));
 	}
 
+	void test_cxx_parser_catches_error_in_macro_expasdsadansion()
+	{
+		std::shared_ptr<TestParserClient> client = parseCode(
+			"void foo() {} \n", { L"-include nothing" }
+		);
+
+		TS_ASSERT(utility::containsElement<std::wstring>(
+			client->errors, L"' nothing' file not found <1:10 1:10>"
+			));
+	}
+
 	void test_cxx_parser_catches_error_in_macro_expansion()
 	{
 		std::shared_ptr<TestParserClient> client = parseCode(
@@ -4068,7 +4079,7 @@ public:
 			client->errors, L"'this_path_does_not_exist.txt' file not found <2:10 2:10>"
 		));
 	}
-
+	
 	void test_cxx_parser_finds_location_of_line_comment()
 	{
 		std::shared_ptr<TestParserClient> client = parseCode(

src/test/helper/TestParserClient.h

@@ -168,7 +168,10 @@ private:
 		bool fatal,
 		bool indexed) override
 	{
-		errors.push_back(addLocationSuffix(message, location));
+		if (location.isValid())
+		{
+			errors.push_back(addLocationSuffix(message, location));
+		}
 	}
 
 	std::vector<std::wstring>* getBinForSymbolKind(SymbolKind symbolType)